Gear-reduction mechanism



June 17, 1930. G, H KQCH 1,764,314

GEAR REDUCTION MECHANISM Filed Sept. 19, 1928 I y* v .1:5

INVENTOR Patented June 17,4 1930 i UNITED STATES PATENT OFFICE l GUsTAv H. 110011,01* WILKINsBUIm,V PENNSYLVANIA, AssIGfNoiay 'ro WEsTING'Housn y nLnc'rnIc` `a`MANUFACTURING COMPANY, A conPonncrIoNor` PENNSYLVANIA l `GEAR-REniIc'rIoN MECHANISM Application mea september 19, 1928. serieu No. aoaaoo.

Y My invention relates, generally, to power- `transmission mechanisms and, particularly, to a speed-reduction gear mechanism.

Y Anobject of my invention isxto provide a 'compact and rugged speed-reduction mechanism which may be utilized in combination with a motor. p A A further object of my invention is to provide a gear-reduction unit embodying drivingand driven members that are `connected by means of a plurality of intermediate gear wheels in'which provision is made for equally vdistributing the torque of the driving members between the several intermediate gear wheels. 1 1.

It is frequently desired to utilize electric power for driving relatively slow-speed ma- ,chine elements. However, as is well known, slow-speed electric motors are of large size and, consequently, are expensive in proportion to the power developed byV them and have relatively low power factor. By the present invention, I have provided a speedvreduction mechanism which may be embodied with a standard high-speed electric motor in such manner that the resulting unit provides an efficient device for furnishing power at relatively slow speeds. e

The foregoing, and other objects, which will be apparent, may be achieved by the Vembodiment of my invention which is described in the following specification and shown in the accompanying drawing in which:

Figure 1 is a view, partially in section and partially in side elevation, of a combined motor and gear-reduction mechanism; and e Fig. 2 is a view, in cross section, of the gear-reduction mechanism taken along the line IIII of Fig. 1.

As shown in the drawing, the' invention is embodied in a slow-speed power unit 1 that comprises, in general, an electric motor 2 of the usual type which is combined with,

and transmits tion unit 3.1 l Y vThe motor 2 comprises the usual stator power through, a gear-reduc- ,I portion 4 which isv provided, at one end, with a4 standard end bell k5 and, atthe other end, with a special end bell or connecting member `6 which is aolapted to support a gearcasing portion 7 for the transmission mechanism 3. The gear casing 7 is provided with a foot orpedestal 8 which, together with a vstandard motor foot 9 that is disposed bemeans of journal bearings 13 and 14, re-

spectively. The journal bearings 13 and 14 are each provided with oil throwers or guards 15 which serve to prevent oil or other matterv from entering the motor 2 by way of the bearings. In order that air may be circulated through the motor for cooling it, the end bell 5 is provided with the usual openings-16 through which air may enter to be passed through the motor .2 and expelled from an opening 17 in the bottom of the special end-bell member 6.

For the purpose of transmitting torque from thernotor rotor 11 to the gear-reduction unit 3, a flexible torque shaft 21 is disposed withiny the hollow shaft 12 in such manner that itis free-to movelaterally, as

well as circumferentially, relative thereto. VIn order to connect the torque shaft 21 to the hollow shaft 12,V a coupling device 22 is provided at the end of the shaft 21 remote from the reduction unit 3. As may be seen in Fig. 2, the other end of the torque shaft 21 is provided with a pinion 23 which projects between, and meshes with, two int-eryiso mediate gear wheels 24 within the gear casing 7. The intermediate gear wheels 24 are mounted upon relatively short shafts 25 which are disposed parallel to, and on the respective sides of, the hollow shaft 12 in a horizontal plane within the gear casing 7.v For transmitting power to a driven member, each of the gear wheels 24 has a pinion 26 fastened to it. The pinions 26 are both disposed to mesh with a driven gear wheel 27 the diameter of which is greater than the distance between the two pinions 26. By means of this particular combination, it is possible to provide a gear mechanism, having a large ratio of speed reduction, thatV may'be disposed within a comparatively small gear case.

As may be seen upon studying Fig. 2 of the drawing, the gear wheely 27 constitutes a positive lock or interconnection between they pinions'26 and, consequently, between the intermediate gear wheels 24. Further, it is apparent that, by reason of this interlocked 'relation between the gear wheels 24, such irregularities or inaccuraciesas ordinarily exist in a gear-reduction mechanism might conceivably be sufficient to cause an unequal distribution of the power transmitted by the pinion 23 to the gear wheels 24. However, in accordance with this invention, by reason of the fact that thepinion 23 is mounted on the end of a relatively long flexible shaft 21, it is free to move slightly, principally in a vertical plane, to automatically adjust itself in such manner vthat the tooth pressure will be substantially equal on 4both sides, and, consequently, the torque transmitted will be divided between the intermediate gear wheels 24 in an advantageous manner.

By reason of this construction, it is possible to make the gear wheel 24 of just sufficient width to carry one half of the total torque of the motor 2, inasmuch as it is not possible to subject one of the gear-wheels 24to all of the torque. Consequently, the

`transmission mechanism may be made compact without sacrificingL ruggedness.

Further, by utilizing the floating-pinion combination, the entire reduction mechanism may be inexpensively made, inasmuch as it is not necessary to machine the parts with a high degree of accuracy.

The driven gear wheel 27 is mounted upon a driven shaft 28 that is journaled in the ygear casing 7 directly above and parallel to the rotor shaft 12 for the purpose of connecting the power unit 1 to a driven member (not shown). The shaft 28 projects from the gear casing 7 through a relatively heavy journal bearing 29 and is provided, at its projecting end, with a key 30 in much the same manner that the shaft of a standard electric motoris extended for engaging a pulley or other driven member;

From a study of the foregoing description, it may be readily seen that my invention provides a compact and rugged power unit for furnishing torque at relatively low speeds.

Although I have described only a single embodiment of my invention, it will be readily appreciated by those skilled in the art that various modification may be made in the general disposition and proportions of the various parts of the speed-reduction mechanism without departingl from the spirit and scope of my invention as defined in the appended claims.v

I claim as my invention 1. A transmission mechanism comprising a hollow driving shaft, a flexible torque shaft disposed within the driving shaft and securedthereto at one end, a driving gear wheel disposed on thetorque shaft and a plurality ofk driven 'gear wheels meshing with the driving gear wheel, said driving gear wheel being adapted to exert equal forces uponthe driven gear wheels by reasons of the adjustment permitted by the flexible torque shaft. 'f

2. A ear-reduction mechanism comprising a ho low driving shaft, a resilient torque shaft disposed within the, hollow driving shaft, coupling means for transmitting torque from the hollow shaft' to the torque shaft, a inion mounted on the torque shaft, anda p urality of gear wheelsdisposed to engage the pinion, said pinion being free to adjust its position relative to the gear wheels by reason of the resilience of Vthe torque shaft.

3.k In a combined motor and gear-reduction unit, the combination with a motor stator structure having a gear casing secured at one end thereof, of a rotor element, a hollow shaft for supporting the rotor, a torque shaft disposed within the hollow shaft,

means for transmitting power from the hollow shaft to the torque shaft, a pinion disposed on the end of thetorque shaft'within the gear casing, two gear wheels disposed at thek sides of, and meshing with, the pinion in suoli manner that the pinion is free to move vertically in order to equalize the torque transmitted to the gear wheels, pinions fastened to the gear wheels, a driven shaft journaled in the casing above the rotor shaft and a driven gear wheel on the driven shaft for engaging the pinions on the two gear wheels.

4. In a power-transmission mechanism, in combination, an electric motor of the usual construction comprisingA a stator portion, a hollow shaft journaled in the stator portion, a rotor mounted on the hollow shaft for cooperating with the stator, a fiexible torque shaft disposed within the hollow shaft, means at one end ofthe hollow shaft for transmitting rtorque to the flexible shaft, a

pinion disposed on the flexible shaft at the end opposite to the torque-transmitting means, gear Wheels for engaging the pinion, supporting means on the stator for journaling the gear wheels, pinions on the gear wheels, a driven gear wheel meshing with the pinion, and a driven shaft for'supporting the driven gear wheel.

In testimony whereof, I have hereunto subscribedvmy name this 11th day of September, 1928.

GUSTAV H. KOCH. 

